1. Field of the Invention
This invention relates to disk drive suspensions, and more particularly to improvements in limiter-featured disk drive suspensions comprising a load beam and attached thereto a flexure comprising a flexure frame and a flexure tongue adapted to carry a slider for increased load-unload efficiency. The invention provides an improved form of limiter structure to that blocks undue movement of the flexure tongue relative to the flexure frame by engaging the tongue free end with the frame in response to an undue excursion of the tongue. The tongue free end-flexure frame contact is localized to a single locus on the tongue free end. This locus is centrally located to avoid possible tipping of the tongue that can occur when outboard limiter structures at the edges of the tongue free end are employed owing to a possible difference in time of engagement. Non-simultaneous engaging contact of the limiters can tip the slider by first raising only one side of the tongue. This does not occur in this invention, since the limiter engagement locus is centrally located and unitary and thus incapable of not being uniform in time of engagement.
2. Related Art
Limiter structures are broadly known. They are generally designed to either prevent excessive excursions during shock events such as the jarring or dropping of the computer, or to prevent damage to the suspension during loading and unloading cycles. These two situations have different requirements. In load-unload, the slider is lifted from the disk against the forces holding it in position including spring loading by the suspension and the vacuum developed between the slider and the rotating disk. Load-unload cycles in present computers occur frequently, particularly in laptop computers, in an effort to conserve power and thus prolong battery life.
It has been suggested to limit flexure tongue travel with slot and tab arrangements with the tab interfitting the slot, the tab extending typically from the load beam and the slot in the tongue, or vice-versa, with fold-over tabs extending from the load beam and embracing the flexure so as to limit the flexure tongue travel, and with expandable ribbons linking the tongue free end with the opposing frame, or attached to the load beam, but these expedients are more complex to satisfactorily manufacture and may be too costly.
The repeating load-unload cycles of lifting and replacing the slider at the disk should not be a source of potential failure of the drive. Nonetheless, inadequate design in the lifter may cause failures. In U.S. Pat. No. 5,771,136, for example, a lifter is disclosed that has left and right sides intended to engage the flexure tongue at both its left and right edges with the opposing frame surfaces. Apparently intended primarily for shock situations, the disclosed lifter in an unloading situation must necessarily engage both left and right tongue edges simultaneously or risk tipping the tongue and thus the slider. Given the close proximity of the slider to the disk, tipping from non-simultaneous, and thus uneven engagement, is to be avoided. Manufacturing tolerances are unlikely to be capable of being held so tight, and manufacturing operations unlikely of being kept so free of mishandling that even a perfect design for simultaneous engagement is not proof against mishaps.
The present invention provides a single contact lifter that is incapable of separated-in-time contact by different parts of the lifter structure, that is thus highly suited to load-unload cycling, and which, in reducing failures, is more efficient as a lifter.
The invention, in particular, provides a disk drive suspension assembly of a flexure and a flexure support, the flexure having a tongue adapted to carry in gimbaling relation a slider in operating proximity to a disk, the flexure support and the flexure tongue defining cooperating structures inboard of the tongue edges, and preferably located within the middle third of the tongue free end width, which limit motion of the tongue relative to the disk to a predetermined range.
In preferred embodiments the cooperating structures comprise a relatively movable structure, such as a hook carried by the tongue and a relatively fixed structure such as the flexure frame surrounding the tongue. The specific form of the cooperating structures is not narrowly critical provided the motion of the tongue free end is restricted past a predetermined point and by a single structure of a single or double or divided wall located centrally of the flexure tongue free end.
More particularly, the invention provides a load-unload efficient disk drive suspension comprising a load beam having a base portion, a spring portion and a rigid portion, and a flexure secured to the load beam rigid portion, the flexure comprising a frame and a generally planar tongue cantilevered from the frame to have a free end spaced from the frame, a limiter structure limiting the relative movement of the flexure tongue and the flexure frame to a predetermined range, the limiter structure comprising a centrally located portion of the tongue free end bent to extend out of the plane of the tongue and shaped to extend beyond the tongue free end to intersect with the flexure frame to limit tongue movement relative to the frame to within the predetermined range.
In this and like embodiments, typically, the flexure tongue free end has an outermost tip, the tip being locally deflected to a plane generally normal to the tongue plane, the tongue free end centrally located portion lies within the central one-third of the lateral width of the tongue free end, or is centered on the tongue free end longitudinal axis of revolution.
In a further embodiment, typically, there is provided a load-unload efficient disk drive suspension comprising a load beam having a base portion, a spring portion and a rigid portion, and a flexure secured to the load beam rigid portion, the flexure comprising a frame and a generally planar tongue cantilevered from the frame to have a free end spaced from the frame, the flexure frame comprising first and second transverse portions and left and right side longitudinally disposed outriggers connected together to define a surrounded opening, the tongue extending into the surrounded opening in cantilevered relation, a limiter structure limiting the relative movement of the flexure tongue and the flexure frame to a predetermined range, the limiter structure comprising a centrally located portion of the tongue free end shaped to extend beyond the tongue free end to intersect with the flexure frame to limit tongue movement relative to the frame to within the predetermined range.
In a further embodiment the invention provides a load-unload efficient disk drive suspension comprising a load beam and a flexure having a tongue with a free end forming a limiter structure, including defining a cut along a transverse line inward of the tongue free end from a first edge of the tongue free end partway across the free end to the centrally located portion of the free end to free a flap of material from the tongue free end and leave an uncut remainder to the second edge of the tongue free end, defining the flap to have a head including the tongue free end first edge and a neck of reduced extent relative to the head such that the flap is hook-shaped and its head portion extends beyond the tongue free end remainder, and bending the flap into a substantially normal orientation relative to the tongue free end to have the head overlie the flexure frame transverse portion opposite the tongue free end in spaced relation corresponding to the predetermined range.
In this and like embodiments, typically, the first and second edges of the tongue free end are spaced laterally of the tongue free end central portion and free of limiter structure, the tongue free end centrally located portion lies within the central one-third of the width of the tongue free end, and the centrally located portion is centered on the tongue free end longitudinal axis of revolution.
In its method aspects, the invention includes the method of forming a limiter structure on a load-unload efficient disk drive suspension comprising a load beam and a flexure, the flexure comprising a frame and a tongue cantilevered from the frame and having a free end, the method including defining a cut along a transverse line inward of the tongue free end from a first edge of the tongue free end partway across the free end to the centrally located portion of the free end to free a flap of material from the tongue free end and leave an uncut remainder to the second edge of the tongue free end, the flap having a head including the tongue free end first edge and a neck of reduced extent relative to the head such that the flap is hook-shaped and its head portion extends beyond the tongue free end uncut remainder, and bending the flap into a substantially normal orientation relative to the tongue free end, whereby the head overlies a the frame transverse portion opposite the tongue free end in spaced relation corresponding to the predetermined range.